JP2000282253A - Rust-proof treatment and rust-proof treated metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive chromium-free anti-rust coating agent having corrosion resistance higher than those of chromium-containing rust inhibitors, a rust-proof treatment process, and a rust-proof treated metallic material. SOLUTION: In this rust-proof treatment process, a steel with or without zinc-type metal coating is subjected to rust-proof treatment by using a first-layer treatment agent containing one or more kinds among 0.1-100 g of phosphoric acid ions, 0.2-200 g of a thiocarbonyl-group-containing compound, and 0.1-100 g of a vanadic acid compound in one liter of water and further optionally containing 10-300 g of water-dispersive silica and also using a second-layer treatment agent optionally containing 0.1-5 g of phosphoric acid ions and 50-500 g of water-dispersive silica in one liter of a composition composed essentially of water-soluble resin and water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust-proofing method for a metal material, in particular, a zinc-based metal-coated steel such as a galvanized steel sheet and the like, and a rust-proofing metal material treated by this method. These rust-proofing metal materials are widely used for home appliances, computer-related equipment, building materials, and industrial products such as automobiles.

[0002]

2. Description of the Related Art Galvanized steel sheets and alloyed galvanized steel sheets have white rust on the surface and significantly impair the appearance not only in an atmosphere containing salt such as seawater, in a high-temperature and high-humidity environment, but also in a normal indoor environment. Also, the rust-preventing force on the base steel surface is reduced.

In order to prevent white rust, chromate-based rust preventive agents have been frequently used.
No. 70 discloses a resin-based rust preventive comprising a water-dispersible chromium compound and water-dispersible silica in an olefin-α, β-ethylenically unsaturated carboxylic acid copolymer resin dispersion. However, even the chromium-containing resin treating agent as described above does not always have sufficient corrosion resistance, and a steel plate that has been subjected to chromate treatment generates white rust when exposed to salt water or a high-temperature and high-humidity atmosphere for a long time. In addition, since a chromium compound has a high risk of harmful effects on the human body, in recent years, a demand for a chromium-free rust preventive agent has been increasing.

The present inventors have found that sulfide ions react with zinc to form a stable ZnS film, and have already disclosed in JP-A-8-239776 and JP-A-8-67834.
Discloses a chromium-free rust preventive agent using sulfide or sulfur. However, some sulfides emit a peculiar odor, and handling is not always easy.

Further, a rust inhibitor using a triazine thiol compound containing a sulfur atom and having no odor or toxicity has been proposed. For example, "Aqueous anticorrosion paint" of JP-A-53-31737 discloses an aqueous anticorrosion paint to which a diol-S-triazine derivative is added. In addition, Japanese Unexamined Patent Publication
Japanese Patent Application Laid-Open No. 1-223062 discloses a reactive emulsion of a metal obtained by mixing a thiocarbonyl group-containing compound with a water-insoluble organic compound in “Reactive emulsion with metal”. However, Japanese Patent Application Laid-Open No. Sho 53-3
The water-based anticorrosion paint disclosed in Japanese Patent No. 1737 is adjusted to be more easily adhered to mild steel or brass. Therefore, it was insufficient as a rust inhibitor for metal surfaces such as zinc. Further, the reactive emulsion disclosed in JP-A-61-223062 is also an emulsion which reacts with copper, nickel, tin, cobalt, aluminum and the like and its alloys. It was not enough.

The present inventors have studied a triazinethiol-containing rust-preventive coating agent which is also effective for rust-prevention of a galvanized steel sheet, and obtained a triazinethiol-containing rust-preventive coating agent described in Japanese Patent Application No. 9-2557. Disclosed. However, triazine thiol is an expensive compound, and a less expensive rust inhibitor has been desired.

[0007] As a surface treatment method for zinc or zinc alloy which does not contain chromium and does not use triazine thiol,
JP-A-54-71734 and JP-A-3-22658
No. 4 publication. JP 5
JP-A-4-71734 discloses that 2 to 6 condensed phosphoric esters of myo-inositol or salts thereof are 0.5 to 100 g / l and are selected from the group consisting of titanium fluoride and zirconium fluoride. Zinc or zinc characterized by surface-treating zinc or zinc alloy with an aqueous solution containing 0.5 to 30 g / l in terms of metal of one or more species and 1 to 50 g / l of thiourea or a derivative thereof. This is an alloy surface treatment method. This technique requires titanium fluoride or zirconium fluoride to form a passivation film as a protective layer on the zinc surface.
Further, in Japanese Unexamined Patent Publication (Kokai) No. 3-226584, one or both of Ni ²⁺ and Co ²⁺ is 0.02 g /
A surface treatment agent which is an aqueous solution having a pH of 5 to 10 and containing one or more compounds having 1 or more and ammonia and a primary amine group is used. This technique requires at least one of Ni ²⁺ and Co ²⁺ in order to impart coating adhesion and corrosion resistance after coating by depositing cobalt or nickel. The treating agents containing these metal ions have disadvantages such as an increase in load during wastewater treatment.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to have a corrosion resistance more than that of a chromium-containing rust inhibitor, which is effective for metal materials such as zinc or galvanized steel sheet. It is an object of the present invention to provide an inexpensive and non-chrome rust-proofing method, and to provide a chromium-free and rust-proofed metal material having excellent corrosion resistance.

[0009]

The rust-preventive treatment method of the present invention is to provide a zinc-based metal-coated steel or an uncoated steel with 0.1 to 100 g of phosphate ion, 0.2 to 20 g per liter of an aqueous solution.
0 g of a thiocarbonyl group-containing compound, and 0.1 to 10
It is characterized in that after coating with a rust-preventive coating agent A containing one or more of 0 g of a vanadate compound, a rust-preventive coating agent B of a composition mainly composed of an aqueous resin and water is coated. .

[0010] The coating agent A is 10 to 300 g
/ L of a water-dispersible silica.

The coating agent B is used in an amount of 0.1 to 5 g per liter of the composition containing the aqueous resin and water as main components.
And at least one of 50 to 500 g of water-dispersible silica.

Further, the rust-proofing metal material of the present invention is treated by the above-mentioned rust-proofing method, the coating amount of the coating layer with the coating agent A is 5 to 100 mg / m ² , The thickness of the layer is 0.1 to 10 μm.

In general, in order to be effective as a rust preventive coating agent, (1) preventing penetration of a corrosive liquid, (2) having an adhesive property of a rust preventive film to a metal substrate,
It is necessary to satisfy (3) passivation of the metal surface by rust preventive ions and the like, and (4) water resistance, acid resistance and alkali resistance of the rust preventive film. If any of these is insufficient, rust prevention cannot be exhibited. The chromium compound of the conventional rust inhibitor was mainly excellent in passivation. Here, the passivation means that a metal or an alloy is in a state of maintaining inertness despite being an environment capable of being activated chemically or electrochemically.

Since sulfides, like chromic acid, are easily adsorbed on the metal surface and have excellent oxidizing ability, they can passivate the metal surface. Therefore, the thiocarbonyl group-containing compound, which is one of the sulfides, has an effect of preventing white rust of zinc plating.

When a vanadium compound is added to the rust preventive containing such a thiocarbonyl group-containing compound, the following rust preventive action of vanadate ions is added, and the rust preventive effect is further promoted. In other words, the vanadate compound is ionized and dissolved in the rust preventive agent, and depending on the compound and the amount added, the dissolved amount as ions is saturated and dispersed as a solid in the rust preventive agent. It may be a pigment. In any case, the vanadate ions form a passive film on the zinc surface during application. This is the reason why the vanadate compound exhibits a rust preventive action.
In addition, when water, which is a corrosion factor, penetrates into the rust-preventive film and a corrosion site is formed on the zinc surface, vanadate ions present in the film and vanadate ions eluted from the vanadate compound by the permeated water. Is thought to act on the corrosion site to suppress the corrosion reaction.

When the vanadate ion coexists with the thiocarbonyl group compound or the phosphate ion, a synergistic action with them is developed. The reason for this synergism is not clear, but vanadate ions form a passive film at sites where phosphate or thiocarbonyl group-containing compounds cannot be adsorbed, or vice versa. It is considered that a phosphate ion or a thiocarbonyl group is adsorbed on a defective portion of the film to supplement the action of the vanadate ion, thereby obtaining a synergistic effect of the anticorrosion action.

Further, when the thiocarbonyl group-containing compound is added together with phosphate ions, its rust-preventing effect is remarkably improved, and a rust-preventive coating agent superior to the conventional chromium-containing resin-based rust-preventing agent is obtained. It is presumed that this is because the rust-preventing effect is exhibited by the synergistic action of the thiocarbonyl group-containing compound and the phosphate ion. That is,
(1) It is presumed that ions of the thiol group in the thiocarbonyl group-containing compound are adsorbed to sites on the zinc surface during the application of the rust-preventive coating agent, thereby exhibiting a rust-preventive effect.
Naturally, a sulfur atom easily forms a coordination bond with zinc, but a thiocarbonyl group (formula 1)

[0018]

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The compound having the formula (2)

[0020]

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As described above, those having a nitrogen atom and an oxygen atom at the same time are more preferable. In these compounds, a nitrogen atom or an oxygen atom can also form a coordination bond with zinc. Therefore, particularly in a thiocarbonyl group-containing compound having these atoms simultaneously, a chelate bond is easily formed on the zinc surface, and a thiocarbonyl group is formed. It is possible for the contained compound to strongly adsorb to the zinc surface. A thiocarbonyl group-containing compound is not adsorbed to sites on the inactive zinc surface (eg, oxide surface), but phosphate ions act on such an inactive surface to form zinc phosphate. To form an active surface. Since the thiocarbonyl group-containing compound is adsorbed on the surface activated in this way, it is presumed that a rust-preventive effect is exerted on the entire zinc surface. Further, (2) both the thiocarbonyl group-containing compound and the phosphate ion act as a crosslinking accelerator of the resin film. It is presumed that the synergistic action of both can reduce the number of micropores in the resin film and efficiently block harmful ions such as water and chloride ions.

It should be noted that, in addition to the excellent rust-preventing action of the above-mentioned thiocarbonyl group-containing compound, phosphate ion and vanadate ion, the addition of water-dispersible silica to this further promotes the rust-preventing action. It was discovered.

The water-dispersible silica adsorbs rust-preventive ions and molecules such as phosphate ions, thiocarbonyl group-containing compounds, and vanadate ions on the silica surface, and appropriately prevents the rust-preventive ions on the zinc plating surface where a corrosion reaction occurs. It is considered that the rust prevention effect is enhanced by releasing rust ions and molecules.

As described above, the rust preventive used in the present invention is extremely effective in attaining passivation of the metal surface by rust-preventive ions and the like. Therefore, it is used as a mixture with an organic resin which is a film-forming component (in the case of the present invention, this organic resin is derived from an aqueous resin due to the properties of the generally water-soluble rust inhibitor of the present invention). However, in order to obtain sufficient performance as a rust-prevention treatment film, the rust-prevention film must have adhesion to the metal substrate, and when a film defect such as a scratch occurs in the rust-prevention film, the metal substrate It is important that the passivating ions be effectively supplied to the However, when a thiocarbonyl group-containing compound, a vanadate compound or a phosphate ion, which is a rust inhibitor in the present invention, is contained in an aqueous resin and applied to a metal substrate and dried, the rust inhibitor concentration on the surface of the substrate is reduced. In some cases, there is a limit to increasing the action of the rust inhibitor because it cannot be consciously increased. Therefore, prior to the application of the coating agent containing the resin, by applying an aqueous solution consisting only of the rust inhibitor, the rust inhibitor reacts sufficiently with the surface of the base material to form a passivation layer, which is further dried and baked. As a result, the rust inhibitor is fixed to the base surface in a sufficient amount, and the adhesion between the subsequently applied aqueous resin layer and the base metal can be dramatically increased. By doing so, even when a film defect such as a scratch is introduced into the rust prevention film,
Since the rust preventive agent is fixed to the surface of the base material, it can be ionized by permeation of water or the like to quickly passivate the scratches on the base surface, thereby significantly improving the corrosion resistance. This effect cannot be attained by a treatment layer in which a resin containing a rust inhibitor is applied in one step.

As described above, in the present invention, the rust preventive coating agent A in an aqueous solution containing at least one of a phosphate ion, a thiocarbonyl group-containing compound and a vanadate compound as a rust preventive agent is used. First, a zinc-based metal-coated steel or uncoated steel is applied, and then a rust-preventive coating agent B consisting of an aqueous resin and water is applied. The coating agent A may optionally include water-dispersible silica, and the coating agent B may further include at least one of phosphate ions and water-dispersible silica.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present invention, the thiocarbonyl group-containing compound is a thiocarbonyl group (1) represented by the following formula:

[0027]

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The compounds having the formula (1) further include compounds capable of releasing a thiocarbonyl group-containing compound in an aqueous solution or in the presence of an acid or an alkali. A typical example of the thiocarbonyl group-containing compound is represented by the formula (3)

[0029]

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Thiourea and its derivatives represented by
For example, methylthiourea, dimethylthiourea, ethylthiourea, diethylthiourea, diphenylthiourea, thiopental, thiocarbazide, thiocarbazones, thiocyanuric acids, thiohydantoin, 2-thiouramil, 3
-Thiourazole and the like; Formula (4)

[0031]

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A thioamide compound represented by the formula:
Is, for example _{-H, -CH 3, -CH 2 CH} 3, -C 6 H
₅ represents _{-C 8 H 5, C 5 H} 3 SO etc.), for example thio formaldehyde, thiocarbonate styryl, thio saccharin; Formula (5)

[0033]

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(Wherein R represents, for example, —H, —CH _3, etc.), for example, thioformaldehyde, thioacetaldehyde, etc .;

[0035]

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(R in the formula represents, for example, —CH ₃ , —C ₆ H _5, etc.), for example, thioacetic acid, thiobenzoic acid, dithioacetic acid, etc .;

[0037]

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And thiocarbonates represented by the formula (1)
Compounds having the structure, for example, thiocoumazone, thiocumotiazone, thionin blue J, thiopyrone, thiopyrine,
Thiobenzophenone and the like can be exemplified. Among these compounds, those that do not directly dissolve in water are once dissolved in an alkaline solution and then incorporated into a rust preventive coating agent.

When the thiocarbonyl group-containing compound in the rust preventive coating agent is less than 0.2 g / l, the corrosion resistance becomes insufficient. On the other hand, when it exceeds 200 g / l, the corrosion resistance is saturated and uneconomical. Becomes

When the amount of the vanadate compound is less than 0.1 g / l, the corrosion resistance becomes insufficient.
If it exceeds, the corrosion resistance is saturated and uneconomical.

The vanadate compound may be a vanadate such as vanadate, ammonium vanadate, sodium vanadate, potassium vanadate, strontium vanadate or sodium hydrogen vanadate, or a phosphovanadate such as phosphovanadate or ammonium phosphovanadate. It can be supplied in the form of salt or the like.

Phosphate ions form a phosphate layer on the metal substrate, passivate it, remarkably improve the adhesion between the resin layer and the substrate, and further inhibit the crosslinking reaction of the resin film derived from the aqueous resin. By accelerating and forming a dense rust prevention film, rust prevention properties are further improved. When the content of phosphate ions is less than 0.1 g / l, the rust-preventing effect is not sufficiently exhibited. On the other hand, when the content exceeds 100 g / l, not only corrosion resistance is saturated and uneconomical, but also In the case of adding to the contained aqueous solution (coating agent B), if it exceeds 5 g / l, depending on the aqueous resin used, the resin gels and cannot be applied. Therefore, the phosphate ion content is 0.1 to 100 g / l for the coating agent A and 0.1 to 5 g / l for the coating agent B.

A phosphate ion source for supplying phosphate ions;
Orthophosphoric acid, condensed phosphorous, ortho metals
Phosphate or condensed phosphate, phosphorus pentoxide, phosphate ore
Product, commercially available composite phosphate pigment, or a mixture thereof
No. Some of the orthophosphates mentioned here are
Monohydrogen salt (HPO_Four ^2-Salt), dihydrogen salt (H_TwoPO_Four ^-
Salt). Water is also contained in the condensed phosphate.
It shall contain salt. In addition, metaphosphate
Acid salts, including ordinary polyphosphate and polymetaphosphate
Shall be included. Specific examples of these phosphorus compounds include
Phosphate minerals such as monetite, tolfillite,
Trock stone, xenotime, star collite, struv
Stone, orchidite, and commercially available complex phosphate pigments such as
Such as silica phosphate, complex phosphoric acid, for example, pyrophosphoric acid,
Metaphosphoric acid and complex phosphates such as metaphosphate, te
Trametaphosphate, hexametaphosphate, pyrophosphate
Salt, acid pyrophosphate, tripolyphosphate, or
These mixtures are mentioned. Metal forming phosphate
The species is not particularly limited, and alkali metals, alkaline earth gold
Genus, metal species of other typical elements and transition metals
It is. Examples of preferred metal species include magnesium and potassium.
Lucium, strontium, barium, titanium, zircon
, Manganese, iron, cobalt, nickel, zinc, aluminum
Luminium, lead, tin and the like can be mentioned. In addition to this
Oxo cations such as thiol, titanyl, zirconyl, etc.
You. Particularly preferred are calcium and magnesium.
You.

The corrosion resistance is further improved by adding water-dispersible silica to the rust preventive coating agent according to the present invention. Moreover, in addition to the corrosion resistance, the drying property, the scratch resistance, and the coating film adhesion can be improved.

In the present invention, the term "water-dispersible silica" is a generic name for silicas having a fine particle size, which can maintain a stable state when dispersed in water and have a property that semi-permanent sedimentation is not recognized. It is something. The water-dispersible silica is not particularly limited as long as it has a small amount of impurities such as sodium and is weakly alkaline. For example, "Snowtex N" (manufactured by Nissan Chemical Industries), "Adelite A"
Commercially available silica gel such as "T-20N" (manufactured by Asahi Denka Kogyo Co., Ltd.),
Alternatively, commercially available aerosil powdered silica particles or the like can be used.

The content of the water-dispersible silica is 10 to 300 g / l for the resin-free coating agent A and 50 to 500 g / l for the resin-containing coating agent B per liter of the rust preventive coating agent. When the content is less than these lower limits, the effect of improving corrosion resistance is insufficient. On the other hand, when the content exceeds these upper limits, corrosion resistance is saturated and uneconomical.

Further, the affinity between the aqueous resin and the silica particles and the pigment (which may be blended as an optional component) is improved, and the adhesion between the aqueous resin and the zinc or iron phosphate layer is further improved. For this purpose, a silane coupling agent or a hydrolyzed condensate thereof or both of them may be blended. Here, the “hydrolysis condensate of a silane coupling agent” refers to an oligomer of a silane coupling agent obtained by subjecting a silane coupling agent to a raw material and hydrolyzing and polymerizing the same.

The silane coupling agent which can be used in the present invention is not particularly limited, but preferred examples thereof include the following: vinylmethoxysilane, vinyltrimethoxysilane, vinylethoxysilane, Vinyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N- (1,3-dimethylbutylidene) ) -3-
(Triethoxysilyl) -1-propanamine, N,
N′-bis [3- (trimethoxysilyl) propyl] ethylenediamine, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ
-Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane,
N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane.

Particularly preferred silane coupling agents are vinyltrimethoxysilane, vinylethoxysilane, 3-
Aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N- (1,3-dimethylbutylidene)
-3- (triethoxysilyl) -1-propanamine,
N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine. One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

In the present invention, the silane compound is an aqueous solution 1
It is used in a concentration of 0.02 to 100 g per liter. If the addition amount of the silane compound is less than 0.02 g, the effect of the addition is reduced, and if it exceeds 100 g, the storage stability decreases, which is not preferable.

The rust preventive coating agent B of the present invention contains an aqueous resin. In the present invention, the term "aqueous resin" includes not only a water-soluble resin but also a water-insoluble resin which is originally water-insoluble but in which the insoluble resin is finely dispersed in water such as an emulsion or a suspension. Examples of resins that can be used as such an aqueous resin include polyolefin resins, polyurethane resins, acrylic resins, polycarbonate resins, epoxy resins, polyester resins, alkyd resins, phenol resins, and other heat-curable resins. And the like, and a crosslinkable resin is more preferable. Particularly preferred resins are polyolefin-based resins, polyurethane-based resins, and mixed resin-based resins of both. The aqueous resin may be used as a mixture of two or more kinds.

The rust preventive coating agent B containing the resin of the present invention is an aqueous resin (including a water-soluble resin and a water-dispersible resin).
Is a composition mainly composed of 1 to 80 parts by weight of solids and 99 to 20 parts of water.
It optionally contains 1 to 5 g, preferably 0.1 to 3 g of phosphate ions, and 50 to 500 g, preferably 100 to 400 g of water-dispersible silica.

Further, the coating agent B of the present invention may further contain other components. For example, pigments, surfactants and the like can be mentioned.

As the pigment, for example, titanium oxide (TiO 2)
₂ ), zinc oxide (ZnO), zirconium oxide (Zr
O), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), alumina (Al ₂ O ₃ ), kaolin clay, carbon black, iron oxide (Fe ₂ O ₃ , Fe ₃
Inorganic pigments such as O ₄ ) and organic pigments can be used.

A solvent may be used in the rust preventive coating agent B containing the resin of the present invention in order to improve the film forming property of the aqueous resin and form a more uniform and smooth coating film. The solvent is not particularly limited as long as it is generally used in paints, and examples thereof include alcohol-based, ketone-based, ester-based, and ether-based solvents.

In the present invention, the above-mentioned rust preventive coating agent A
And B are used as a rust-preventive coating agent for metal materials such as zinc-coated steel or uncoated steel, and such metal materials are subjected to rust-proof treatment. This rust prevention treatment, first, after applying a resin-free rust-preventive coating agent A to the object to be coated, the object to be coated is heated and dried with hot air, and then a resin-containing rust-preventive coating agent B is applied, It can be carried out by a method of heating and drying.

The heating temperature is set to 5 in both the layer containing no resin (first layer) and the layer containing resin (second layer).
0-250 ° C is suitable. If the temperature is lower than 50 ° C., the evaporation rate of water is too slow to obtain a sufficient film-forming property, so that the rust-preventing ability is insufficient. On the other hand, when the temperature exceeds 250 ° C., particularly in the case of a system containing a resin, thermal decomposition of the aqueous resin occurs, so that the salt spray resistance and the water resistance are reduced, and the appearance is yellowed. Is done. The drying time when the object to be coated is heated with hot air after application and dried is preferably 1 second to 5 minutes.

In the above rust preventive treatment, the amount of the rust preventive coating agent of the present invention is preferably 5 mg / m ² or more for the first layer (layer made of the coating agent A). If it is less than 5 mg / m ² , the adhesion and corrosion resistance of the second layer (the layer made of the coating agent B) will be insufficient. On the other hand, the upper limit is desirably 100 mg
/ M ² is good. If the amount of adhesion is too large, the effect as a coating base treatment is saturated and uneconomical, and more preferably,
A ^{5mg / m 2 ~50mg / m 2} . The coating method is not particularly limited, and the coating is performed by a dipping method, a coater coating method, a spray coating method, or the like. After coating, the object to be coated is heated in a hot air oven,
Heat in an H furnace or the like and dry.

The coating thickness of the second layer of the rust-preventive coating agent B is desirably a dry thickness of 0.1 μm or more.
If it is less than 0.1 μm, the rust-preventing ability is insufficient. On the other hand, if the dry film thickness is too large, problems such as cracks during processing occur and it is uneconomical, so that the thickness is preferably 20 μm or less, more preferably 0.1 to 10 μm. The coating method is not particularly limited, and the coating can be performed by generally used roll coating, air spray, airless spray, dipping, or the like. After the application, the object to be coated is heated in a hot air oven, a direct fire oven, an IH oven, or the like, and dried.

Materials coated with the rust preventive coating agent of the present invention include zinc-based metal-coated steel and uncoated steel as described above. The zinc-based metal-coated steel is specifically galvanized, zinc and Fe, Ni, Co, Cr,
It refers to a steel material plated with an alloy of one or more of Mg, Al, Si, and Mn. Further, the same effect can be obtained with Al-coated steel. Al-coated steel is specifically made of Al plating or Al and Si, Mg, Mn, F
e, a steel material plated with an alloy of one or more of Ni, Co, Cr and the like. The plating method is not particularly limited, and an electroplating method, a hot-dip plating method,
Any method such as a vacuum plating method may be used. The steel material is not particularly limited, but may be a cold-rolled steel sheet, a hot-rolled steel sheet, a thick plate, a steel bar, a steel pipe, or the like.

Further, the rust preventive coating agent of the present invention can be used as a so-called primary rust preventive, as well as being used as a paint base treating agent and an aqueous rust preventive paint as described above. Furthermore, it can be used not only for the undercoat treatment and the undercoat treatment of the lubricating film of the galvanized steel sheet in the field of coil coating, but also for the lubricating steel sheet by adding a wax to the rust preventive coating agent containing the resin of the present invention. It can also be used as a lubricating rust inhibitor.

Next, the present invention will be further described with reference to examples. In each of the following examples, the concentration expressed in g / l means the content (g) of each component contained in 1 liter of the rust preventive coating agent. In each of the following examples, the evaluation of corrosion resistance was performed by the following method.

[Evaluation Method] (A) Rust Prevention a) Preparation of Specimen Amount of the rust prevention coating agent A containing no resin of the present invention applied to a commercially available electrogalvanized steel sheet EG-MO material with a bar coat # 3. After applying the solution to a concentration of 30 mg / m ² , it was dried to a final plate temperature (PMT) of 70 ° C., air-cooled, and then coated with a rust preventive coating agent B containing the resin of the present invention using a bar coat #.
3. After applying so that the dry film thickness becomes 1 μm in 3
It was dried to 150 ° C.

B) Salt Spray Test A 5% saline solution was sprayed on the surface of the object to be coated at 35 ° C. by a test method in accordance with JIS Z2371, and the degree of white rust after 240 hours was evaluated on a scale of 1 to 10. The evaluation was performed for both the flat portion and the Ericksen 7 mm extruded portion. The evaluation criteria were as follows. 10 points: No abnormality 9 points: Between 10 and 8 points 8 points: Slightly white rust generated 7 points to 6 points: Between 8 and 5 points 5 points: White rust generated in half the area 4 to 2 points : Between 5 points and 1 point 1 point: White rust occurred on the entire surface

(B) Topcoat Adhesion a) Preparation of Specimen A rust preventive coating agent A containing no resin of the present invention was applied to a commercially available electrogalvanized steel sheet EG-MO material with a bar coat # 3 in an amount of 30 mg / m ^2. After applying so that PMT7
After drying to 0 ° C. and air cooling, a rust-preventive coating agent B containing the resin of the present invention was applied using a bar coat # 3 to a dry film thickness of 1 μm, and then dried to a PMT of 150 ° C. Was. After drying, Super Rack 100
(Nippon Paint Co .; acrylic melamine paint) was applied by a bar coat to a dry film thickness of 20 μm and then PM
It was dried at T150 ° C. for 20 minutes to produce a topcoat adhesion test plate.

B) Primary adhesion test Cross cut: Tape releasability was evaluated at a portion where a cut of 1 mm was cut, and it was evaluated on a scale of 10 out of the following criteria. Erichsen 7 mm: A tape was applied to a portion extruded with Erichsen to 7 mm, and the tape peelability was similarly evaluated. Cross-cut + Erichsen 7 mm: A tape with a cut of 1 mm in cross-section was extruded to 7 mm with Erichsen, and a tape was applied thereto, and the tape peelability was similarly evaluated. The evaluation criteria were as follows. 10 points: No abnormality 9 points: The percentage of peeling out of the grids measured was 10% or less 8 points: ２０ 20% or less 7 points: ３０ 30% or less 6 points: ４０ 40% or less 5 points: ５０ 50% or less 4 Points: 〃60% or less 3 points: 〃70% or less 2 points: 〃80% or less 1 point: ９０90% or less 0 points: 大 Greater than 90%

C) Secondary adhesion test After immersing the test plate in boiling water for 30 minutes, the same test and evaluation as the primary test were performed.

Example 1 Ammonium phosphate was dissolved in pure water so as to have a phosphate ion concentration of 0.1 g / l, and dispersed by stirring with a disper for 30 minutes. A layer of rust-proof coating agent A was obtained. On the other hand, polyolefin resin "HITEC S-70" is added to pure water.
24 "(trade name; manufactured by Toho Chemical Co., Ltd.) so that the concentration of resin solids becomes 20% by weight, and 30
After stirring and dispersing for 2 minutes, the pH was adjusted to 8.0 to obtain a second layer rust preventive coating agent B. In order to evaluate the obtained rust preventive coating agent for primary rust preventive property and top coat adhesion, as described in the above evaluation method, a commercially available electrogalvanized steel sheet “EP-MO” (Nippon Text Panel Co., Ltd.) , 70 × 150 × 0.8 mm) and dried. The electrogalvanized steel sheet was degreased with an alkali degreasing agent ("Surf Cleaner 53", manufactured by Nippon Paint Co., Ltd.), washed with water, and dried, and then evaluated as described above. Table 1 shows the compositions of the rust-preventive coating agents A and B used, their adhesion amounts and film thicknesses, and Table 3 shows the evaluation results. (Examples 2 to 41) In Example 1, the addition amount of the phosphate ion in the first layer, the type and the addition amount of the thiocarbonyl group-containing compound, the addition amount of Snowtex-N (water-dispersible silica), the vanadate The amount of the compound added, the type of the water-soluble resin in the second layer, the amount of the phosphate ion, and the amount of the Snowtex-N were changed as shown in Tables 1 to 3, respectively. The same evaluation was performed, and the results shown in Tables 5 to 7 were obtained. In Examples 34 to 41, the following silane compounds (silane coupling agents) were used. A: vinyltrimethoxysilane B: vinylethoxysilane C: 3-aminopropyltriethoxysilane D: 3-glycidoxypropyltrimethoxysilane E: 3-methacryloxypropyltrimethoxysilane F: 3-mercaptopropyltrimethoxysilane G: N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine H: N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine (Comparative Examples 1 to 5) 8) The phosphate ion concentration in Example 1,
The same evaluation as in Example 1 was performed by changing the concentrations of thiourea, Snowtex-N, and the vanadate compound as shown in Table 4, and the results shown in Table 8 were obtained.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

[Table 5]

[0074]

[Table 6]

[0075]

[Table 7]

[0076]

[Table 8]

[0077]

As described above, according to the rustproofing method of the present invention, excellent rustproofing properties can be obtained. Moreover, the components used in the rust preventive coating agent of the present invention have low toxicity, and therefore, according to the present invention, it is possible to perform a non-chrome rust preventive treatment having low pollution and excellent rust preventive ability. Further, since the rust-preventive metal material treated by the rust-preventive treatment method of the present invention has a film formed thereon, it is possible to effectively suppress the generation of rust.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Atsushi Morishita 1 Kimitsu, Kimitsu City, Chiba Prefecture F-term in Kimitsu Works 4D075 AE03 CA33 DA06 DB02 DB05 DC12 DC18 EA06 EB01 EB02 4K026 AA02 AA07 AA12 BA01 BA03 BA09 BA12 BB06 BB08 BB10 CA16 CA23 CA24 CA25 CA26 CA30 CA37 CA39 CA41 DA15 DA16 4K062 AA01 BA08 BA14 BA17 BB21 BC07 BC08 BC12 BC15 CA02 FA12 FA16 GA08

Claims (4)

[Claims] 1. A method according to claim 1, wherein 0.1 to 100 g of phosphate ions per liter of an aqueous solution are added to the zinc-based metal-coated steel or uncoated steel.
After coating with 0.2 to 200 g of a thiocarbonyl group-containing compound and 0.1 to 100 g of a rust preventive coating agent A containing one or more of vanadate compounds, an aqueous resin and water are mainly used. A rust-preventive treatment method comprising coating a rust-preventive coating agent B of a composition to be formed. 2. The coating agent A is 10 to 300 g.
The method according to claim 1, further comprising 1 / l of a water-dispersible silica. 3. The coating agent B is used in an amount of 0.1 to 5 per liter of a composition containing the aqueous resin and water as main components.
The method according to claim 1, further comprising at least one of g of phosphate ions and 50 to 500 g of water-dispersible silica. 4. The method according to claim 1, wherein the coating amount of the coating layer with the coating agent A is 5 to 100 mg / m ² , and the coating with the coating agent B is performed. A rust-proofing metal material having a layer thickness of 0.1 to 10 μm.